It is widely assumed that ultimate attainment in adult second language (L2) learners often differs quite radically from ultimate attainment in child L2 learners. This article addresses the question of whether learners at different ages also show qualitative differences in the process of L2 acquisition. Longitudinal production data from two untutored Russian beginners (ages 8 and 14) acquiring German under roughly similar conditions are compared to published results on the acquisition of German by adult immigrants. The study focuses on the acquisition of negation and finiteness as core domains of German sentence grammar. Adult learners have been shown to produce an early nonfinite learner variety in which utterance organization relies on principles of information structure rather than on target language grammar. They then go through a couple of intermediate steps in which, first, semantically empty verbs (auxiliaries) serve as isolated carriers of finiteness before lexical verbs become finite. Whereas the 14-year-old learner of this case study basically shows a developmental pattern similar to that of adults, the 8-year-old child produces a different order of acquisition: Not only is the development of finite morphology faster, but finite lexical verbs are acquired before auxiliary constructions (Perfekt). Results suggest a stronger tendency for young learners to incrementally assimilate input patterns without relying on analytic steps guided by principles of information organization to the same extent as older learners.